Sleep apnea is a common but serious and potentially life-threatening condition affecting millions of Americans. Sleep apnea is a breathing disorder characterized by brief interruptions (e.g., 10 seconds or more) of breathing during sleep. There are two types of sleep apnea: central and obstructive. Central sleep apnea, which is relatively rare, occurs when the brain fails to send the appropriate signal to the breathing muscles to initiate respirations.
Obstructive sleep apnea (OSA) is far more common. FIG. 1A is an anatomic view of a person with an open upper airway. Normally, the muscles of the upper part of the throat keep the airway open to permit air flow into the lungs. When the muscles of the upper airway relax and sag, the relaxed tissues may vibrate as air flows past the tissues during breathing, resulting in snoring. In more serious cases, as seen from FIG. 1B, the airway becomes blocked, making breathing labored and noisy, or even stopping it altogether. In a given night, the number of involuntary breathing pauses or “apneic events” can be quite frequent. A lack of air intake into the lungs may result in lower levels of oxygen and increased levels of carbon dioxide in the blood. The altered levels of oxygen and carbon dioxide alert the brain to resume breathing and may cause the sleeper to struggle and gasp for air. Breathing will then resume, often followed by continued apneic events. There are potentially damaging effects to the heart and blood vessels due to abrupt compensatory swings in blood pressure. Upon each event, the sleeping person will be partially aroused from sleep, resulting in a greatly reduced quality of sleep. The frequent interruptions of deep, restorative sleep may lead to early morning headaches, excessive daytime sleepiness, depression, irritability, and learning and memory difficulties. OSA may also increase the risk of heart attacks, hypertension, and strokes.
One solution for easing the onset of OSA is the Continuous Positive Airway Pressure (CPAP) machine. The CPAP machine accomplishes this by delivering a constant stream of compressed air at a prescribed pressure level (also called the titrated pressure) via a hose to a nasal pillow, nose mask or full-face mask. Thus, the airway is splinted and remains open under the air pressure, resulting in a reduction and/or prevention of apneas and hypopneas. However, while effective, the CPAP machine suffers from numerous disadvantages. For example, having to wear a mask strapped around one's head may be cumbersome and uncomfortable. Additionally, the CPAP machine is very noisy which may make it difficult for the user (or anyone nearby) to sleep. Moreover, aerophagia or swallowing too much air, a common cause of gas in the stomach and belching, can be caused by the CPAP.
Another solution for easing the onset of OSA involves surgery. For example, uvulopalatopharyngoplasty, tonsillectomy, surgery to correct severe retrognathia and tracheostomy may be conducted. While these procedures may be effective in some patients, there is a potential for scarring of tissue, which may actually exacerbate the problem.
Yet another solution for easing the onset of OSA involves the surgical implantation of magnets within the human body. An example of such a solution is described by Nelson et al., in U.S. Pat. No. 7,188,627 entitled, MAGNETIC FORCE DEVICES, SYSTEMS, AND METHODS FOR RESISTING TISSUE COLLAPSE WITHIN THE PHARYNGEAL CONDUIT, filed on Sep. 6, 2003. By implanting similarly polarized magnets on opposing sides in a tissue region in a lateral pharyngeal wall along a pharyngeal conduit, the repulsion of the magnets may be enough to resist collapse of the soft wall tissue, thereby resisting the cause of OSA. However, this approach suffers from numerous disadvantages. For instance, one disadvantage is that the opposing magnetic forces are constantly being applied. As such, for example, the user will feel the repulsion even when the user is awake. Moreover, the constant application of the opposing magnetic forces would make eating and swallowing very difficult and uncomfortable. Another disadvantage is that because the opposing magnetic forces are constantly being applied, the user may accidentally come into contact with other ferromagnetic material which may also cause discomfort. Yet another disadvantage is that the constant application of force against the tissue may constrict the blood flow out of the surrounding tissue area, which may cause cell death. Yet another disadvantage is that while it may be possible to adjust the strength of the magnets before they are surgically implanted, there is no way to adjust the strength of the magnets after they are surgically implanted, except for surgically removing and/or replacing the magnets.
Therefore, there remains a need for an intelligent device for alleviating OSA that is not cumbersome to the user.